


Of Potions and Puzzles

by LyraNgalia



Series: Murder on the Hogwarts Express [5]
Category: Harry Potter - J. K. Rowling, Sherlock (TV)
Genre: Alternate Universe - High School, Alternate Universe - Hogwarts, F/M, Gen, Marauders' Era, Potions, rare pair bingo
Language: English
Status: Completed
Published: 2014-11-18
Updated: 2014-11-18
Packaged: 2018-02-26 03:19:26
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,762
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2636090
Author URL: https://archiveofourown.org/users/LyraNgalia/pseuds/LyraNgalia
Summary: <blockquote class="userstuff">
              <p>Irene Adler and Sherlock Holmes are two of the most brilliant minds in Slytherin, but their interests rarely intersected despite a mutual fascination. But a mystery offers just the right excuse...</p>
            </blockquote>





	Of Potions and Puzzles

**Author's Note:**

> Written for the Sherlock Rare Pair Bingo prompt "beginning".

As a rule, Irene trusted very few people in her life. Even fewer still within Hogwarts' walls. But in her mind, trust was an unnecessary thing, not when she knew what people liked, when she understood what they wanted, and how to trade what they wanted for what she wanted, and usually without their realizing anything at all.  
  
Usually.  
  
This time, however, and with this particular individual, that sort of guile would be seen through. But, that meant other games would be necessary, and Irene did love games that made the monotony of Hogwarts days more exciting.  
  
There was a Slytherin/Gryffindor Quidditch game going on that afternoon and the halls of Hogwarts Castle were still and empty save for the occasional house elf who slipped away without a sound at the approach of human feet. Irene strode through the castle corridors with sure steps, her heels clicking loudly on the stones. Her robes swept behind her like a living shadow, and she held her pale hawthorn wand loosely between her fingers.  
  
The door to the Potions classroom was firmly closed, just like all the other classrooms, but Irene flicked her wand at it and the lock clicked quietly open. A triumphant smirk on her lips, she pushed the door open without a sound, her wand still held loose but at the ready as she did.  
  
"Locked doors are meant to keep people out, Miss Adler," a distracted yet distinctly annoyed voice informed her. Irene shut the door behind her with an audible click, pointedly leaving it unlocked, and crossed her arms.  
  
"Then perhaps you should have secured it better, Mr. Holmes," she answered unrepentantly, raising an unimpressed eyebrow at her fellow Slytherin sitting at one of the potions benches, surrounded by three small cauldrons, each bubbling with a liquid of different colour. She moved into the room, the hem of her robes swaying against her legs as she did, her heels clicking crisply against the stone. He did not flinch from her, though his eyes did flicker down to the wand in her hand, and Irene's smirk grew. "But then you know locked doors draw my attention, just like puzzle boxes do yours."  
  
He rolled his eyes then, though a tense pull at the corner of his mouth before he caught the gesture gave away his irritation at her correct statement. "Was that your simple trinket I found in the dormitory?" he asked, feigning exaggerated boredom. "Child's play."  
  
She laughed at his response, low and amused, and his mouth tightened again, watching her as she took a seat on the desk, within arm (and wand) reach of the left-most cauldron. "Was that why it took you the better part of a month to open it?" He opened his mouth to protest and she added, "You knew there was a spell on it to destroy the box after three incorrect tries. Did you really think it wouldn't tell me when you actually got it right?"  
  
A small smile played at his mouth. "So you knew I'd solve it," he answered, satisfied.  
  
She smirked, the corner of her mouth tugging upward in something that was almost a genuine smile. Or as genuine as Irene Adler got. "Of course. I wanted you to."  
  
His expression grew sour as he processed the implication of her statement and Irene leaned towards him, tapping her wand against the rim of the bubbling cauldron. Her words were soft, conspiratorial, as she continued, "So you've solved the puzzle, Mr. Holmes. But have you figured out the mystery?"  
  
His eyes drifted to her mouth, inked in deep blood red, and lingered for a moment too long, snapping back to her eyes when her lips quirked into a knowing smile.

  
"Wolf fur and human hair. Student, obviously male by the length, colour. Monkshood, pilfered from the class stores," he sneered, pale blue eyes blinking rapidly before he turned away from her and back to his cauldrons, as if dismissing her. "Obvious that you want me to think of werewolves, and of potions. Equally obvious that you're too smart to think you can create a potion to become a werewolf."  
  
She dipped her head in acknowledgment, utterly unfazed by his attempted digs at obviousness. "Good," she prompted, tapping at the bubbling cauldron again, the motion causing a golden spark to leap from the potion surface. "You've figured out what I _don't_ want. Now can you figure out what it means?"  
  
This time he swatted her wand away. "Potions are delicate," he informed her, peeved. She spun her wand between her fingers, and arched an eyebrow at him, her body language clear. _I'm waiting_. He huffed out a long-suffering breath and continued, "You want a potion, otherwise you wouldn't come to me. The fur and hair suggests you already know of a werewolf." His eyes widened and a spark of keen interest warred with his attempt to project a look of boredom.  
  
"A werewolf who is a _student_ ," he breathed, the revelation seeming to energize him, as he tented his fingers to his lips, his eyes focused on some imaginary thing in the middle distance. "But not the student whose hair you gave me, you wouldn't be that obvious. This is a secret you want to keep for yourself as long as possible." He focused on her then, pale blue eyes sharp. "You keep secrets. You use what people want to make people do what you want. And the most obvious thing a werewolf student would want is to be _normal_ ," he added with a sneer.  
  
A pleased smile began to play on Irene's lips, growing slowly as she watched him, a look of triumph in her own pale eyes. But she kept silent, watching as his fingers tapped against his lips, against each other, as if he were unravelling a knot. "You want a potion to make a werewolf human," he finally said. "You want to dangle a prize in front of your wolf and see if he bites."  
  
"Five points to Slytherin," she said. Her fingers drummed against the heavy scarred wood of the desk as she continued, “You want to know who the werewolf is. And you know I won't just tell you. Which means the best way of uncovering that particular secret is giving me bait and seeing who leaps.” She slid off the table with little more than a whisper of cloth, and gave him a look over her shoulder. "And the challenge of a wolfsbane potion, Mr. Holmes? Something that they've said for years cannot be invented? The impossible problem? It would seem right up your alley."  
  
Her eyes positively gleamed, sparkling ice blue rings surrounding a wide, dark pupil, and despite himself and his constant reminder that he worked _alone_ , Sherlock could not help the way a thrill of anticipation ran up his spine at the possibility. To prove that the idiots and their theories were wrong, to discover just who this supposed werewolf was in the school, to observe Irene Adler's plans and gain insight into the woman whose very presence at Hogwarts irritated him to no end for her presence and her unreadable elusiveness.  
  
Oh but that could be _fun_.  
  
A small anticipatory smile began to pull at his lips and Sherlock opened his mouth to answer, but she spoke again, smug and knowing, her voice like opium smoke, curling into his brain. "I'll be in touch, Mr. Holmes."  
  
And she was gone, back out of the potions classroom with quick, confident strides as her voice lingered in his mind. There was something absolutely infuriating about that, about how she seemed to stun and stymie him at every turn. Sherlock huffed and turned his attention back to his potions.  
  
The Polyjuice potion in the center cauldron was bubbling away, its colour exactly as noted by his potions book. The potion on his right would not be ready for ages, and he ignored it for the moment. The one on his left, however, the one closest to where the woman had sat, he turned back to that one with interest, his fingers already flipping through his book to the appropriate page, comparing characteristics.  
  
Yes, the sheen on its surface was beginning to coalesce, to grow pearly and reflect pastel colours in its milky depths, a gleam of pink swirling into a rich vein of ice blue the exact colour of Irene Adler's eyes--  
  
The comparison stopped Sherlock short and he shook his head, as if he could dispel the idea through physical action. He turned back to his potion, consulted its ingredients list and its characteristic traits again. He stirred the contents of the pot, and smiled in satisfaction as steam began to rise from its surface in characteristic spirals.  
  
He leaned in close to the cauldron and took a deep breath. According to the ingredients added to the potion, he should have been able to recognize the scent of roses, the faint whiff of salt, and the acrid bitterness of burned parchment, among other things. Sherlock did not for a minute believe in the idea that he would smell whatever his heart desired.  
  
Love was, after all, a chemical defect, and Sherlock prided himself on his lack of sentiment, a surety that convinced him he could not be affected by Amortentia. He breathed deep, but all he could detect was the smell of worn leather, and the scent of sandalwood and vanilla, the lingering traces of Irene Adler's perfume, hanging in the air where she had lingered far too close to his cauldron.  
  
Sherlock frowned and looked down at his table, rolling his eyes as he noticed the leather glove sitting too close to his burner where he had laid it earlier. That explained the leather, at least. He tossed the glove carelessly over his shoulder and used his book to waft the air above his cauldron clear of the smell of leather, of the scent of Irene Adler's perfume, and leaned down again for another deep breath.  
  
Leather. Sandalwood. Vanilla. And beneath the mingled scents, the faintest hint of the acrid itch of burning parchment.  
  
Sherlock sighed and waved his wand at the cauldron with a single word, extinguishing the smoldering fire beneath. There had been too many distractions, clearly. Too many interruptions and too much interference for him to tell what Amortentia _really_ smelled like. Another day then. He stood up, stretched, and ran a hand through his face. Another day, after he'd begun thinking on the puzzle of wolfsbane.  
  
And he'd gotten the smell of sandalwood and vanilla from his nostrils.


End file.
